Sixths can be major, minor, augmented or diminished. Below you can see
that the number of steps determines the quality of the interval:
Diminished sixth, 3 1/2 whole steps or 7 half steps
Minor sixth, 4 whole steps or 8 half steps
Major sixth, 4 1/2 whole steps or 9 half steps
Augmented sixth, 5 whole steps or 10 half steps
The easiest way to identify the quality of a sixth is by inverting the
interval and identifying the resulting third. For example, the interval C#-A#:
- The inversion is A#-C#.
- We identify the resulting third.
- A#-C# is a minor 3rd. so C#-A# is a major 6th.
A major 6th becomes a minor 3rd when inverted
See Identifying Intervals by using Inversions for more information.